An individual lawsuit, perhaps, but if it the violations were shown to be a regular, even systematic problem, then it could lead to a court-appointed monitor to oversee changes or even direct management of large portions of the particular police force.
Again, that’s not going to happen unless the systemic violation is actually, you know, causing problems. I doubt that a federal court would issue some sort of order forcing oversight of a police department for its practice of stopping people and handing out goodies at Christmas, at least in the absence of a showing that the stops ended up being used for more serious purposes regularly.
md2000, the case law on when evidence can be used following an improper stop is all over the place. We start with the basic exclusionary rule laid down by the Supreme Court of the United States in Weeks v. U.S., back in 1914 (the origins go back even further) as applicable to Fourth Amendment violations. This was a federal rule only until the SCotUS applied it to state court proceedings in Mapp v. Ohio. At that point, the basic rule applicable in all state court criminal cases was that any evidence obtained as a proximal result of an unconstitutional search or seizure was to be excluded from use against the defendant.
Having reached this high-water mark (as fleshed out over several decisions later during the Warren Court and Burger Court years), various decisions have begun to chip away at the edges of the concept. For example, there are the inevitable discovery exception, the good faith reliance exception, the reasonable means test (Florida v Jimeno), etc. Of course, once the Court establishes an exception, prosecutors try to drive the larges vehicle they can through that exception, leading to other cases that seal the edges (like the case you discussed with the unreasonable seizure while they went and got a drug dog). Trying to formulate a specific rule under these circumstances is almost impossible. 
Nothing to add to the OP, but I do want to say Thanks to pkbites for sticking to this thread and to the Dope. There has been a fair bit of skepticism from people with personal stories that have come across to me as antagonistic toward police in general. Pkbites has worked right through that and tried to provide a reasoned and fact-based discussion. Just like we hope to see on the Dope. I appreciate his effort and his patience. In his place I would have just dropped out and the thread and Dope would have been the worse for it.